1. Field of the Invention
The present invention relates to electrical circuits. More particularly, the present invention relates to a baseband filter start-up circuit.
2. Background Information
Electrical circuits can have various operating modes, such as, for example, a power-down mode, where no current is flowing in the circuit, and a steady-state operating mode, where the circuit is conducting the calculated current(s). Start-up circuits have been used in many of such circuits to push the operation of the electrical circuit from the power-down mode into the steady-state operation. The start-up circuit injects an initial current into the electrical circuit, and once steady-state operation of the electrical circuit has been obtained (i.e., the circuit is conducting the calculated current(s)), the start-up circuit is turned off.
In, for example, a wireless transceiver, one or more components of the transceiver may not start-up themselves during initial power-up. For example, the components may be in a power-down state. Inputs to these components may be initially pulled down to ground so that no current passes through the components, as it is not desirable to consume power while the transceiver is in a power-down state. However, these transceiver components may have an unpredictable state (e.g., either high or low) at the beginning of operation when powering up, which can have an affect on obtaining subsequent steady-state operation of these components and the transceiver. Therefore, to have a predictable state when powering up, it is desirable to assist the start-up of such components.